Method and apparatus for filling closed containers with volatile liquids



Oct. 2, 1956 w. E. MOOYAART' 2,764,873 METHOD AND APPARATUS FOR FILLINGCLOSED CONTAINERS WITH VOLATILE LIQUIDS Filed June 3, 1953 FIG. ]I

WVENTOE WlLLEM E. MD Y A Q 5y 7 7W Hi5 AT TOQNEY Patented Oct. 2, 1956METHOD AND APPARATUS FOR FILLING CLOSED CONTAINERS WITH VOLATILE LIQUIDSWillem E. Mooyaart, The Hague,

to Shell Development Company, corporation of Delaware Application June3, 1953, Serial No. 359,255 Claims priority, application NetherlandsOctober 2, 1952 9 Claims. (Cl. 62-1) Netherlands, assignor Emeryville,Calii'l, a

This invention relates to the art of dispensing volatile liquids intoclosed containers having inlet means for liquid and outlet means forvapor. More particularly, the invention relates to an improved methodand apparatus for filling such closed containers with volatile, readilyevaporable liquids, such as liquefied hydrocarbons of which propane andbutane are examples.

When volatile liquid is admitted into a closed container, the spaceavailable within the container for vapor originally present therein andvapor resulting from evaporation of the admitted volatile liquid withinthe container will decrease progressively as the quantity of liquidwithin the container increases; consequently, the vapor will becompressed, resulting in a temperature rise in the vapor. A part of thisvapor is condensed upon coming into contact with the surface of theliquid within the container and as the heat of condensation resultingtherefrom cannot be distributed rapidly enough throughout the entireliquid mass by natural causes, the temperature prevailing at the liquidsurface is higher than the temperature of the liquid below such surface.This compression of the vapor and non-uniform temperature distributionhave heretofore caused the pressure of the vapor within the container toexceed the vapor pressure of the liquid corresponding to the mean liquidtemperature.

Various means have heretofore been proposed to obviate or amelioratethis pressure rise in the vapor space. To permit the vapor to escape tothe ambient atmosphere is usually undesirable, not only because suchvapors are often hazardous due to their combustibility, but also becauseof the attendant lossof the valuable materials. The vapor space of thecontainer to be filled is therefore often connected to the vapor spaceof the reservoir from which the liquid is withdrawn during the fillingoperation. If, however, the distance separating the reservoir and thecontainer is considerable, this expedient can create difficulties owingto the great length of the connecting vapor conduit; thus, long vaporconduits bring about changes in temperature and present resistance tothe passage of the vapor. Moreover it is common practice to install ameter between the supply reservoir and the container to be filled forregistering the quantity of liquid dispensed to the container. Whenvapor is vented to the atmosphere or returned to the reservoir, thereresults a loss to the customer, who is receiving the liquid in theclosed container, of vapors that have already been metered to him, andthis makes it necessary to give him an estimate allowance for suchlosses; such allowances are diflicult to estimate.

It has also been proposed to feed the volatile liquid into the vaporspace at the top of the container to be filled instead of into theliquid space at the lower part of the container, so as to insure abetter contact and heat transfer between the liquid being introduced andthe vapor already present in the container, resulting in a bettercooling of the latter, owing to the falling of the introduced liquidthrough the vapor and onto the liquid surface;

there is then also a slight improvement in the distribution of the heatof condensation to the lower, colder layers of the liquid within thecontainer because of greater turbulence. It has been found in practice,however, that this method does not bring about a sufiicient cooling ofthe vapor to eliminate the above noted ditlicu-lty and to obviate theneed for vapor dischargelines.

Finally, it is already known to draw the vapor out 'of I the vapor spacewithin the container to be filled by means of a mechanically driven gaspump or blower and, after compressing and cooling this vapor, to feed itinto the liquid stream flowing into the container. This expedient has adrawback that a special gas pump and power source are required.

It is a general object of this invention to provide an improved methodand apparatus for filling closed containers with volatile liquids,whereby the above-m entioned drawbacks are avoided. t

More particularly, it is an object of the invention to provide a methodand apparatus of the type described in which the container to be filledneither communicates by a vapor conduit with the reservoir from whichthe liquid is withdrawn, nor is provided with a vapor outlet or ventthrough which the vapors are vented to the ambient atmosphere orconducted to an extraneous point of disposal.

According to the invention, which does not requirea return vaporconduit, while losses of vapor are avoided, an eductor, also known. asan ejector, is inserted into the liquid supply conduit,,preferablydown-stream from the meter if provided, and a suction side of'the'eductor is connected to the vapor space of the container to befilled. The volatile liquid is supplied from a source outside of thecontainer at a suitable pressure, for example by a liquid pumpor from anelevated or a pressurized reservoir, and is, prior to discharge into thecontainer, flowed through the eductor as a moving liquid column ofsubstantial velocity in lateral communica-tio-n'with the low pressurezone of the eductor, thereby generating a pressure decrease therein;vapors produced by partial vaporization of the liquid (or of similarliquid previously stored in'the container) are thereby drawn from thecontainer and transferred into said low pressure zone from which theyare drawn into the moving column of liquid and thereby intimately mixedtherewith, causing complete, direct heat exchange. The resulting mixtureis then introduced into the container, thereby progressively increasingthe contents thereof. The eductor or ejector, which is activated by thefresh volatile liquid supplied thereto, not only draws in vapor from thevapor space of the container, but also brings about an intimate contactbetween the vapor and the liquid, so that vapor condenses and/ ordissolves in this liquid and the temperature is almost uniformthroughout all parts of the liquid mass within the container.

The invention can be applied both for filling stationary tanks frommobile reservoirs, for example, when filling stationary storage tanksfrom trucks, as well as for filling tanks mounted upon vehicles, trucks,boats, or the like, or for filling smaller portable vessels, forexample, the usual pressure cylinders. I v

The invention will be further described in detail with reference to theaccompanying drawing forming a part of this specification, illustratingtwo specific embodiments by way of illustration, wherein:

Figure 1 is a diagrammatic elevation view of an installation for fillinga vehicle-borne container or a truck from a stationary reservoir; and

Figure 2 is a similar View of a part of a modified installation.

Referring'to the drawings in detail, a storage reservoir 1 containingvolatile liquid is connected to a liquid pump scribed above. Forexample,

2 by a supply line 3. A meter 4 may be connected into the pump dischargeline 3a which conducts the volatile liquid under moderate pressure to aneductor 5. In the latter, the volatile liquid is discharged from anozzle 6 which is aligned with and spaced from a convergingdivergingtube 7, and the liquid flows as a moving column in lateral communicationwith an annular low pressure zone or space 8. The tube 7 discharges intoa flexible liquid discharge conduit 9 having a valve 10. The lowpressure zone 8 is connected by a flexible suction conduit 11 to a valve12. The parts described to this point may be parts of a stationaryinstallation.

The container to be filled is shown as a tank 14 mounted I on a truck15; it has a liquid inlet 16 at the bottom and a vapor outlet opening 17at the top. These openings communicate with conduits 18 and 19,respectively, having values 20 and 21 and suitable coupling devices 22and 23 by which they may be connected to the liquid and vapor conduits 9and 11.

In operation, the eductor is activated by volatile liquid from thereservoir 1 which flows at a substantial velocity from the nozzle 6 intothe convergent-divergent tube 7, thereby generating a low pressure inthe zone 8 and drawing vapors in the vapor space V of the container 14through the vapor conduit 19 and open valves 21 and 12. These vapors aredrawn in from the low pressure zone 8 into the moving column of volatileliquid and become condensed and/or dissolved in the liquid as a resultof the intensive contact therewith within the ejector and the conduitsdownstream therefrom. This causes direct heat exchange between vapor andliquid. As a result of this action heat of condensation is rapidlydistributed throughout the moving liquid and the temperature of theresulting mixture flowing from the eductor is raised. This mixture flowsthrough the open valves and 20 and is introduced into the container 14through the inlet 16 whereby the liquid contents of the containerundergo a gradual temperature rise with a resultant pressure rise, butthis pressure rise is considerably lower than that which would occur inthe vapor space V if no vapor were discharged therefrom. The enteringliquid mixture is slightly warmer than the liquid already in the tank,but the temperature difierence is small. The turbulence and eddycurrents naturally resulting tend to reduce the temperature difference.The liquid within the container 14 is thus brought to a more or lessuniform temperature, whereby the temperature of the vapors in the spaceV is lower than it would be if no vapors were withdrawn and thetemperature were not equalized. This reduction of the pressure rise inthe tank 14. has the advantage that the pump 2 need not act against toohigh a pressure, while the tank 14 may, if desired, be made of a lighterconstruction. The pressure at which the liquid is supplied to theeductor 5 need be only slightly in excess of that of the ultimatepressure in the tank 14, although moderately greater pressures will beemployed usually to attain a higher rate of de 'very to the container14.

The quantity of volatile liquid withdrawn from the reservoir 1 isregistered by the meter 4. It is evident that all of this material isultimately delivered into the container 14 with the system describedabove.

It should be understood that certain changes can be made in thearrangement and disposition of the parts dethe eductor 5 need not beinstalled as a part of the dispensing system; it could, for example, becarried on a part of the vehicle and a coupling 24 may be provided, bywhich the delivery line 3a can be connected thereto. Furthermore, thereservoir 1 may be located at an elevation or be maintained underpressure, so that the pump 2 can be omitted.

Moreover, the eductor 5 may be mounted entirely within the container 14,as shown in Figure 2, at any desired level, e. g., at the bottom. Theeductor is connected to a vapor pipe 19a, situated entirely within thetank 14 and having vapor intake openings 17a near the top forcommunication with the vapor space at the top of the tank space intocommunication with the annular low pressure zone 8 of the eductor. Thevolatile liquid is delivered from the delivery line 3a which isconnected by the coupling 24 to the supply pipe 25 leading to the inletnozzle of the eductor. The discharge tube 7 of the eductor dischargesdirectly into the tank 14. The operation of this device corresponds inall respects to that previously described, except that the vapor pipe19a and eductor are entirely within the container 14.

As already stated, the application of the invention is not restricted tothe filling of railroad or vehicular tank cars, but can also be used tofill other vessels, both stationary and portable. The invention can alsobe used to fill vessels of containers with liquids other than theprescribed light hydrocarbons, for example ammonia, carbon dioxide,sulfur dioxide, and the like.

The invention is not restricted to the application of the type ofejector as described before, but any type of gaswithdrawi'ng eductor orejector may be used.

I claim as my invention:

1. Method of filling a closed container with volatile liquid comprisingthe steps of: flowing volatile liquid from a source outside saidcontainer and prior to discharge into the container at substantialvelocity through an eductor and generating a low pressure therein;withdrawing vapors from said container solely by the action of saidgenerated low pressure and transferring said vapors to the eductor, saidvapors having substantially the composition of vapor resulting frompartial vaporization of said volatile liquid; intimately mixing thetransferred vapors with said liquid supplied to the eductor and etfectngdirect heat exchange between the vapors and liquid; and progressivelyincreasing the contents of said container by introducing the resultingmixture of liquid and vapor into the container.

2. Method according to claim 1 including in combination therewith theadded steps of flowing said volatile liquid prior to flow into theeductor through a metering device for measuring the quantity of saidliquid and measuring said quantity of liquid by said device, whereby allof said measured quantity of liquid is delivered to the container.

3. Method of filling a closed container with volatile liquid comprisingthe steps of: flowing volatile liquid from a source outside saidcontainer and prior to discharge into the container as a moving columnof substantial velocity in lateral communication with a low pressurezone to generate the low pressure in said zone; drawing from saidcontainer vapors resulting from partial vaporization of said liquid andtransferring said vapors into said low pressure zone by the action ofsaid generated low pressure; drawing said transferred vapors from saidlow pressure zone into the moving column, thereby mixing the vapors withthe liquid and eifecting direct heat exchange between the liquid andvapor; and progressively increasing the contents of said container byintroducing the resulting mixture of liquid and vapors into thecontainer.

4. Apparatus for filling a closed container with volatile liquidcomprising, in combination: an eductor having a liquid pressure inlet, aliquid outlet communicating with said container for discharging liquidfrom the eductor to said container, a low pressure zone, and a suctioninlet communicating with said low pressure zone; means for supplyingsaid volatile liquid under pressure from a source outside of thecontainer directly to said liquid pressure inlet; and vapor conduitmeans interconnecting an upper part of said container and said suctioninlet for withdrawing vapors from the container to the low pressure zoneby the action of said eductor and mixing said vapors with the liquidflowing through the eductor while progressively increasing the contentsof the container.

5. Apparatus according to claim 4 wherein said means for supplying saidvolatile liquid is provided with a meter for measuring and registeringthe quantity of volatile liquid supplied to said pressure inlet of theeductor.

6. Apparatus according to claim 4 wherein the eductor is situatedexternally with respect to said container and the said liquid outlet andthe said vapor conduit means are connected to the bottom and top of saidcontainer, respectively.

7. Apparatus according to claim 6 wherein said eductor is a part of adispensing system including a supply reservoir as a part of said meansfor supplying liquid, said liquid outlet communicates to said containerthrough a liquid conduit having a detachable coupling, and said vaporconduit means includes a conduit having a detachable coupling.

8. Apparatus according to claim 4 wherein the eductor and vapor conduitmeans are mounted on the container to be filled and the liquid pressureinlet has a detachable coupling connecting said inlet to the means forsupplying liquid under pressure.

9. Apparatus according to claim 8 wherein the eductor is situated withinthe container.

References Cited in the file of this patent UNITED STATES PATENTS WadeNov. 17, 1936 Melke Jan. 11, 1944 Garretson Nov. 15, 1949 Hansen Nov.21, 1950 FOREIGN PATENTS Great Britain Oct. 10, 1898

